Localization of Dlg at the mammalian neuromuscular junction.

Recent studies have begun to elucidate the localization of ion channels and receptors in central nervous system synapses. A family of proteins containing PDZ domains has been suggested to play essential roles in these processes. PSD-95 and chapsyn-110 have been implicated in the clustering of Shaker K+ channels and NMDA receptors in the mammalian brain, and Dlg plays a role in the clustering of Shaker K+ channels at the Drosophila neuromuscular junction (NMJ). We have explored whether Dlg might participate in mammalian NMJ organization. We demonstrate that Dlg is expressed in muscle and co-localizes with utrophin at the post-synaptic face of the mammalian NMJ. Dlg may therefore be important for establishing or maintaining the organization of protein complexes at the mammalian NMJ.